Encrypted Traffic Monitoring for User Pair Identification

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Solution Overview

Problem

Existing systems face challenges in identifying relationships between users of encrypted communication applications without decrypting messages, especially when applications use servers as intermediaries and generate diverse traffic patterns, making it difficult to monitor communication sessions effectively.

Innovation Solution

A monitoring system that scans communication traffic for message sequences following predetermined patterns, calculates the likelihood of user pairs communicating, and generates outputs indicating related user pairs without decrypting messages, using machine-learned models and n-grams to identify patterns in encrypted traffic.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encrypted protocols are used for communication traffic, then security and privacy are improved, but the ability to monitor and identify user relationships is worsened

Engineering Contradiction:
ImprovesecurityVSAvoiduser relationship identification
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces an intermediary monitoring system that captures encrypted traffic between users and the application server. This intermediary extracts metadata features (timing, packet size, frequency) without decrypting the content, enabling relationship identification while preserving encryption security. The server acts as another intermediary that routes all user traffic through a single port, concentrating monitoring capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional content-based analysis (mechanical decryption and inspection) with statistical and machine learning-based analysis of encrypted traffic patterns. Instead of examining message content, the system uses algorithms to analyze timing, frequency, and size patterns to identify user relationships, substituting cryptographic mechanisms with statistical inference.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If message content inspection is performed to identify user relationships, then relationship detection accuracy is improved, but processing time and computational resources are worsened

Engineering Contradiction:
Improverelationship detection accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts only the necessary metadata features from encrypted traffic (timing, packet size, frequency) without extracting or decrypting the actual message content. This extraction approach achieves sufficient relationship detection accuracy while avoiding the time-consuming process of full message inspection and decryption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system performs preliminary feature extraction and filtering on captured traffic before applying complex machine learning algorithms. By pre-processing the traffic to identify relevant metadata and filter out irrelevant data, the system reduces computational complexity and processing time for the main relationship identification task.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If all communication traffic is monitored to ensure comprehensive user relationship identification, then detection completeness is improved, but system complexity and resource consumption are worsened

Engineering Contradiction:
Improvedetection completenessVSAvoidmonitoring system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The application server acts as a central intermediary that all user traffic must pass through via a single port. This architectural design enables comprehensive monitoring of all user relationships without requiring complex distributed monitoring systems, as all encrypted traffic is concentrated at one monitoring point.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The monitoring system is designed to handle multiple user relationships and diverse traffic patterns through a unified analysis framework. The machine learning model is trained to recognize various communication patterns across different user pairs, enabling the system to identify all relationships using a single versatile detection mechanism rather than multiple specialized systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11336609B2System and method for identifying pairs of related application users
Publication Date: 2022.05.17 COGNYTE TECH ISRAEL LTD
  • US11336609B2 patent drawing
  • US11336609B2 patent drawing
  • US11336609B2 patent drawing

AI summary

Systems and methods for passive monitoring of computer communication that does not require performing any decryption. A monitoring system receives the traffic exchanged with each relevant application server, and identifies, in the traffic, sequences of messages—or “n-grams”—that appear to belong to a communication session between a pair of users. Subsequently, based on the numbers and types of identified n-grams, the system identifies each pair of users that are likely to be related to one another via the application, in that these users used the application to communicate (actively and/or passively) with one another. The system may identify those sequences of messages that, by virtue of the sizes of the messages in the sequence, and/or other properties of the messages that are readily discernable, indicate a possible user-pair relationship.